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A B commented on DERBY-2526:
----------------------------
> I thought that the transitive closure processing was only looking at join conditions,
> not at simple restriction conditions ("tt2.c2 = 3"), but perhaps I was wrong.
There are two types of transitive closure:
http://db.apache.org/derby/docs/dev/tuning/ctuntransform37032.html
The first is join conditions, as you've noticed. The second is "search conditions" and does
indeed take into account predicates like "tt2.c2 = 3", so maybe this is why you are seeing
the different plans?
> Wrong query results due to column ordering in UNION view
> --------------------------------------------------------
>
> Key: DERBY-2526
> URL: https://issues.apache.org/jira/browse/DERBY-2526
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.0.2.1, 10.1.3.1, 10.2.2.0, 10.3.0.0
> Reporter: Bryan Pendleton
> Assigned To: Bryan Pendleton
> Attachments: badQuery.log, derby-2526.sql, DistinctTestNotes.txt, firstTryPatch.diff,
goodQuery.log
>
>
> I think both select statements in the attached repro script should return 1 row, but
in fact the first statement returns 1 row and the second returns zero rows.
> The only difference between the two statements is that the columns in the UNION view
are listed in a different order (bvw vs. bvw2).
> This seems like a bug to me; the order of the columns in the view definition shouldn't
matter, should it?
> As Army noted on the derby-dev list, the fact that this reproduces with 10.0 means that
it is not caused by some of the 10.2 optimizer changes. Something else is going wrong.
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